In current client-server systems, servers cannot reach clients and transmit data to them whenever new data is available. In other words, a client must send a request message to a server to fetch new data. To solve this problem, the introduction of a connectivity server is proposed on the following website, https://labs.ericsson.com/apis/web-connectivity/
FIG. 7 shows a system including such a connectivity server 106 connected to a public network 107, such as the Internet. In the system, terminal devices 101 and 105, and a home gateway 102 are client devices of the connectivity server 106. Further, the home gateway 102 may have one or more control interfaces for electric devices, such as a digital versatile disc (DVD) recorder 103 and a television (TV) receiver 104. In FIG. 7, the home gateway 102, a terminal device 101, the DVD recorder 103 and the TV receiver 104 are placed in a home 200 of a user.
The connectivity server 106 maintains a connection to a client device after authenticating the client device by an identifier and a password assigned to the client device or the user. After establishing connections between the connectivity server 106 and client devices 101, 102 and 105, terminal devices 101 and 105 as well as the home gateway 102 can freely transmit data via the connectivity server 106. For example, a terminal device 105 can send control information of the DVD recorder 103 to the home gateway 102, which the home gateway 102 outputs to the DVD recorder 103. The home gateway 102 can also upload the status of the DVD recorder 103 and/or TV receiver 104 to the terminal device 105. The user can monitor status information regarding each electric device in the home 200 from any client device via the connectivity server 106. As described above, the connectivity server 106 provides a connectivity service to client devices.
The connectivity server 106 requires authentication of client devices. In other words, the user of the client device must remember the combination of an identifier and a secret value, such as a password, and input the combination to establish a connection with the connectivity server 106. The identifier and the associated secret value are normally generated off-line.
It is convenient if the identifier and the associated secret value can be automatically generated and stored on each client device of the connectivity server 106.